Server initiated power mode switching in portable communication devices

ABSTRACT

In a process, a power mode indicator is transmitted from a content server and is received by a Portable Communication Device (PCD). The indicator is indicative of a power mode potentially available to a circuit block in the PCD. The circuit block exhibits different levels of power consumption when operated in different power modes and is operated in the indicated power mode in response to the received power mode indicator. The content server may be a stream server. The circuit block may be operated in the power mode to receive/process a data stream.

FIELD OF THE INVENTION

The present invention relates to portable communication devices, serversthat communicate with such devices, and methods of setting power modesin such devices.

BACKGROUND OF THE INVENTION

A portable communication device (PCD), also referred to as personalcommunication device, such as a cell phone is often powered by abattery, which has a limited lifetime. To extend the lifetime of thebattery, a conventional PCD can automatically switch between low andhigh power consumption modes based on a given triggering event orcondition. Different power modes can be selected depending on whether aparticular component or function of the device is active or not. Forinstance, a cell phone may switch between an inactive mode and an activemode depending on whether the user is actively using the cell phone. Thecell phone is normally set to an inactive, and low power consumption,mode when it is not actively used. The cell phone is set to an active,and high power consumption, mode when it is actively used, such as tomake a phone call or to play media content received over a wirelessnetwork by way of data streaming.

Accordingly, it is desirable to provide alternative or improved powersaving techniques for PCDs.

SUMMARY OF THE INVENTION

Power saving may be achieved in a PCD, such as a cell phone, byadjusting or setting the power mode in the PCD based on a power modeindicator received from a content server. The content server may be astream server, and the PCD or a circuit block thereof may be operated inthe power mode when playing media content streamed from the server. Forinstance, the power mode indicator may be determined based on one ormore of the bitrate of the streamed data, a graphics resolution of thestreamed video images, a compression ratio of the streamed data, and thelike. The power mode indicator may indicate one of a number ofpre-selected power levels, such as low and high, or low, medium andhigh. A functional circuit block in the device for receiving orprocessing the streamed data may be set to the indicated power mode,independent of the current power mode of the device or other functionalcircuit blocks of the device.

Accordingly, in accordance with an aspect of the present invention,there is provided a method of operating a portable communication device(PCD), comprising receiving, from a content server, a power modeindicator indicative of a power mode selected from a plurality of powermodes available to a circuit block in the PCD, the circuit blockexhibiting different levels of power consumption when operated indifferent ones of the power modes. The method also comprising operatingthe circuit block in the power mode in response to the received powermode indicator. The content server may be a stream server. The methodmay comprise receiving a data stream for a media content from the streamserver; and processing the data stream for presentation of the mediacontent to a user, as the data stream is being received, the circuitblock operating in the power mode to perform at least one of thereceiving and processing the data stream. The PCD may transmit to thestream server data indicative of a processing capacity, where a reducedpower mode may be selected when the processing capacity is higher thanneeded to process the data stream. The power modes may comprise a fullpower mode and at least one reduced power mode.

In accordance with another aspect of the present invention, there isprovided a method of operating a content server, comprising transmittingto a portable communication device (PCD) a power mode indicatorindicative of a power mode that may be available to a circuit block inthe PCD, the circuit block exhibiting different levels of powerconsumption when operated in different power modes; and transmittingdata to the PCD. The content server may be a stream server. Transmittingdata to the PCD may comprise transmitting a data stream for a mediacontent to the PCD, while the data stream is received and processed bythe PCD for presentation of the media content to a user and the circuitblock is operated in the power mode to perform at least one of receivingand processing the data stream. The stream server may receive from thePCD data indicative of a processing capacity, and select a reduced powermode when the processing capacity is higher than needed by the PCD toprocess the data transmitted to the PCD.

In the above described methods, the power modes may include a full powermode and at least one reduced power mode. The power mode may be selectedbased on at least a bitrate of the data stream. The data stream maycomprise compressed data, and the power mode may be selected based on atleast a compression ratio of the compressed data. The media content maycomprise video images and the power mode may be selected based on atleast a graphics resolution of the video images. The data stream maycomprise a television broadcast signal. The television broadcast signalmay comprise a sideband, and the power mode indicator may be transmittedin the sideband. The PCD may communicate with the content server throughwireless or wired communication.

According to another aspect of the present invention, there is provideda PCD comprising a circuit block operable in a plurality of power modes,the circuit block exhibiting different levels of power consumption whenoperated in different ones of the power modes; a receiver for receiving,from a remote content server, a power mode indicator indicative of apower mode selected from the plurality of power modes; and a powermanagement module for setting the circuit block to operate in the powermode in response to receiving the power mode indicator. The contentserver may be a stream server. The circuit block may be operated in thepower mode to perform at least one of receiving and processing streameddata for media content. The PCD may be a cellular telephone.

According to another aspect of the present invention, there is provideda content server. The content server comprises a power mode selector forselecting a power mode indicator indicative of a power mode selectedfrom a plurality of power modes potentially available to a circuit blockin a portable communication device (PCD), the circuit block exhibitingdifferent levels of power consumption when operated in different ones ofthe power modes. The content server also comprises a transmitter fortransmitting to the PCD the power mode indicator and data. The contentserver may be a stream server. The power mode indicator may beassociated with a data stream for media content to be transmitted to thePCD such that the circuit block is operable in the power mode to receiveor process, or both receive and process, the data stream forpresentation of the media content to a user.

Other aspects and features of the present invention will become apparentto those of ordinary skill in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures, which illustrate, by way of example only, embodiments ofthe present invention,

FIG. 1 is a block diagram illustrating communication between a contentserver and a portable communication device;

FIG. 2 is a flowchart of possible operations performed at the contentserver of FIG. 1;

FIG. 3 is a flowchart of possible operations performed at the portablecommunication device of FIG. 1;

FIG. 4 is a schematic block diagram of a communications network;

FIG. 5 is a schematic block diagram of a portable communication deviceshown in FIG. 4;

FIG. 6 is a flowchart of possible operations performed by the streamingserver shown in FIG. 4;

FIG. 7 is a flowchart of possible operations performed by the device ofFIG. 5;

FIG. 8 is a flowchart of alternative operations performed by thestreaming server of FIG. 4; and

FIG. 9 is a flowchart of alternative operations performed by the deviceof FIG. 5.

DETAILED DESCRIPTION

FIG. 1 shows exemplary embodiments of the present invention, where mediacontent (MC) is provided from a content server 100 to a portablecommunication device (PCD) 102. Media content may be transmitted fromcontent server 100 to PCD 102 by way of data streaming, in which case,content server 100 may be a stream server.

Media content is any audio, visual or multimedia content that can bedisplayed or played, and may include a live feed, such as a television(TV) or radio broadcast signal. Media content may also include othercontent including other audio or video content. The media content mayinclude music, songs, photographs, images, recorded video, movie,recorded or live events or shows, such as entertainment performances, TVshows, sporting events, news events, conferences, seminars, or lectures,and the like.

The phrase “content server” is used broadly herein and includes anysignal originating or relaying device, apparatus, station, server,transmitter, or the like. For example, content server 100 may be abroadcast station such as a TV station, a cell phone network basestation, an antenna for transmitting signal, another PCD or wirelessdevice such as a cell phone or a media player, a home computer,entertainment device or the like. Content server 100 may include atransmitter 112 for transmitting data to PCD 102 and a power modeselector 114, the use of which will be come clear below.

PCD 102 may be any portable, mobile, or handheld electronic device thatcan communicate with a remote server and play media content. Forexample, PCD 102 may be a cellular telephone adapted to also play mediacontent. Other portable or mobile devices such as Blackberry™ devices,short-message-service (SMS) devices, personal digital assistant (PDA)devices, portable computers, or the like may also be used as PCDs ifthey are capable of communicating with a remote content server toreceive streamed media content and playing it.

As depicted in FIG. 1, PCD 102 may include a battery 104 for providingpower thereto, a power management module such as power controller 106,and an electronic circuit powered by battery 104 which includes an MCcircuit block 108 and other optional circuit blocks 110. MC circuitblock 108 may be configured to process the streamed data forpresentation of the media content carried by the stream to a user.Processing of the streamed data may include decoding the streamed dataand presenting the media content decoded from the streamed data. MCcircuit block 108 may include a receiver (not shown) for receivingstreamed data from content server 100. Other circuit blocks 110 may beconfigured for performing other necessary or optional functions of thedevice, such as voice communication functions in a cell phone. Areceiver (not shown) may be included in circuit blocks 110. Whilecircuit blocks 108 and 110 are depicted as separate functional blocks inFIG. 1, the actual circuits for them may be separate or integrated.

During data streaming, data for the media content is transmitted from afirst location, such as content server 100, to a second location, suchas PCD 102, while the media content is being displayed or played at thesecond location, such as PCD 102. The transmitted stream may also becontinuous. The term “continuous” or “continuously” does not necessarilyrequire that the transmission of data is constant. A continuoustransmission may include relatively short intervals of non-transmissionor idle time, either regularly or irregularly. As can be appreciated,short interruptions of data transmission are common in network orwireless transmission. The data stream for the media content may betransmitted over a network such as a wireless network or cellularnetwork, as will be further described below.

It is typical to compress the content data for transmission by datastreaming, such as to increase transmission speed or reduce thebandwidth required for its transmission. Thus, during data streaming,PCD 102 may perform several functions including communicating with thecontent server 100 to receive the compressed content data, decompressingthe compressed data as it is received, and playing the decompressedcontent data. MC circuit block 108 of PCD 102 may include one ormultiple separate functional blocks for performing one or more of thesefunctions, as will be further described below.

PCD 102 may be capable of receiving and displaying different types ofmedia content, including both audio and video contents. Different mediacontents may require different processing powers during data streaming.For example, the compression ratio is typically higher for highresolution video data than for audio data or low resolution video data.Further, high resolution video may require higher transmission speedthan audio or low resolution video do. In addition, displaying highresolution video or graphics may require more calculation by agraphics-rendering circuit at PCD 102. Consequently, the processingpower required to receive, decompress/decode, and display/play differentmedia contents can vary. To conserve battery power during datastreaming, one or more of the relevant functional circuit blocks of PCD102, such as MC circuit block 108 may be set to one of a number ofpre-selected power modes, based on a power mode indicator (PMI) receivedfrom content server 100. When operated in different power modes, MCcircuit block 108 exhibits different levels of power consumption. Thevalue of the PMI may be determined by mode selector 114 of contentserver 100, as will be described further below.

The pre-selected power modes may include a low power mode and a highpower mode. The high power mode may be a full power mode, and the lowpower mode is a reduced power mode. Optionally, the power modes mayinclude multiple reduced power modes, such as a low power mode and amedium power mode. In different embodiments, more than three modes maybe made available.

The PMI may be implemented in any suitable manner as can be understoodby those skilled in the art. For example, the indicator may include asingle digit, which may have a binary value such as “0” or “1”, where“0” may indicate a low power mode and “1” may indicate a high powermode.

The PMI may be determined based on one or more factors that can affectpower consumption. One factor that can affect power consumption is thebitrate of the media content to be transmitted and played. Bitratetypically refers to the number of bits that are transmitted or processedper unit time. For multimedia content, bitrate may refer to the numberof bits used per unit time to represent a continuous signal such asaudio or video signal. For a given media content that is compressed, thebitrate may vary depending on the data compression technique. Contentswith a higher bitrate may require more power to transmit, decode andplay. The compression ratio of the streamed data can also affect powerconsumption. A higher compression ratio may mean that more power isneeded to decompress the data. Another factor is the graphics resolutionof the visual images included in the media content. A still or videoimage with higher resolution may require more power to process such asdecode or display.

For illustration purposes only, in the description below it is assumedthat the PMI is determined based on the bitrate of the media content.The following description may be readily modified by those skilled inthe art for situations in which other factors are considered fordetermining the PMI.

In one embodiment, mode selector 114 may be configured to determine thePMI based on a bitrate for the segment of data stream to be transmittednext. The bitrate may be specified in a header portion of the datastream, or be obtained from a separate source such as a database. Modeselector 114 may be adapted to determine the PMI by comparing thebitrate with a threshold. For example, when the bitrate is higher thanthe threshold, the PMI may be set to “1” and when the bitrate is lowerthan the threshold, the PMI may be set to “0”. The threshold may bepre-selected and stored at content server 100, or a remote locationaccessible by mode selector 114. Alternatively, the threshold may bedynamically determined, such as based on information received from PCD102. For instance, processing capacity information of PCD 102 may betransmitted to content server 100 so that the threshold can bedetermined based on such information.

Optionally, mode selector 114 of content server 100 may be adapted toobtain from PCD 102 the available power modes or possible values of thePMI. Mode selector 114 may also obtain, such as from PCD 102,information related to correlation between the bitrate and the values ofPMI. Content server 100 may also maintain or communicate with a databaseof possible types of PCD devices and the necessary data or informationfor determining the PMI for each particular type of PCD device. Thus,once the type of the PCD device is identified, the information necessaryfor obtaining the PMI based on a given bitrate may be retrieved and usedby mode selector 114 in subsequent operations.

The PMI, once determined, may be transmitted from content server 100 toPCD 102 in any suitable manner. For instance, the indicator may beembedded in the header portion of the media content data stream, or in asideband of a TV signal when the transmitted media content is TVbroadcast signal.

As can be appreciated, mode selector 114 may be implemented in eithersoftware or hardware, or a combination of both. Mode selector 114 andtransmitter 112 may be integrated or may be provided as separatecomponents. Mode selector 114 and transmitter 112 may be located at thesame location or at different locations.

During operation, content server 100 and PCD 102 may respectivelyoperate as illustrated in FIGS. 1 to 3, where FIG. 2 illustratespossible operations performed at content server 100 and FIG. 3illustrates possible operations performed at PCD 102.

As illustrated, a communication channel is established between contentserver 100 and PCD 102 for transmitting data therebetween, includingdata for media content.

Before a segment of media content is transmitted, content server 100obtains a bitrate associated with the segment of media content about tobe transmitted (at S202) and determines the PMI based on the bitrate (atS204), as described above. For illustration purposes, it may be assumedthat a fixed bitrate threshold has been pre-selected and the bitrate ofthe media content is compared with the threshold. In an exemplary casewhere the bitrate is assumed to be lower than the threshold, the PMI maybe selected to have a value of “0”, indicating the low power mode.

The PMI is then transmitted to PCD 102 (at S206).

PCD 102 receives the PMI (at S302) and sets the power mode of circuitblock 108 based on the value of the PMI (at S304). In the exemplarycase, the power mode may be set to the low power mode. Alternatively, oradditionally, PCD 102 may use other factors in addition to the value ofthe PMI to set the power mode of PCD 102. Such other factors mayinclude, for example, other applications or power consuming clients thatmay be operating on PCD 102 in addition to the application that is to beused to process the transmitted content.

Content server 100 transmits the associated segment of the media contentto PCD 102 (at S208), which is received, decoded and presented at PCD102 at S306 while circuit block 108 is operated in the selected powermode. In the exemplary case, PCD 102 will process the segment ofstreamed data while circuit block 108 is in the low power mode.

If there is a further segment of media content to be streamed(determined respectively at S210 and S308), the above process isrepeated at content server 100 and PCD 102 respectively. Otherwise, theprocess of data streaming may be terminated.

In different embodiments, a segment of MC may have a pre-determinedlength of display time, file size, or the like, and may be marked bystarting and ending data bits embedded in the streaming data. The PMIitself may serve as the starting or ending marker. Thus, the end of asegment can be determined accordingly.

As discussed above, the header field of each data packet may include abit field for PMI, where the bit may represent a high (1) or a low (0)power mode. In an alternative embodiment, when there are only twopossible power modes available, the header field may include a PMI bitrepresenting toggle (1) or no-toggle (0). In such a case, when twoconsecutive segments of media content can be processed in the same powermode, the PMI bit may be set to “0” to indicate no switch of power modeis needed, and when the two segments require different power modes toprocess, the PMI bit may be set to “1”, indicating a switch of powermode is needed.

It may not be necessary to change the power mode when there is no changein the bitrate, compression ratio, and image resolution in the streameddata. In such a case, the PMI bit may be set to the previous value orset to “no-toggle”. When one or more of the relevant parameters for thenext segment change, the PMI bit may be set to a new value or set to“toggle”.

It may now be appreciated that in some embodiments, the bitrate of themultimedia content may be a more accurate measure of the average powerconsumption requirement than the bitrate of data transmission. In someembodiments, the two bitrates may be different and may be bothconsidered for determining the PMI.

FIG. 4 illustrates a communications network 400, exemplary ofembodiments of the present invention. Communications network 400includes a streaming server 410 that may stream multimedia data througha data network 412, a backbone network 414, and a radio access network416 to a portable communication device (collectively and individuallyreferred to as PCD 420). Multimedia data may include video or audiodata, or both, that may be presented or displayed to a user of a PCD420.

The streaming server 410 is interconnected to data network 412, whichtransfers data to backbone network 414. As will be appreciated by aperson of ordinary skill, data network 412 may be any data communicationnetwork such as the Internet, an Intranet, a local area network, and thelike. Data network 412 may employ known network protocols such as TCP/IPand RTP/RTSP. Backbone network 414 may be any high capacity network thatjoins multiple networks together. As shown in FIG. 4, backbone network414 joins data network 412 and radio access networks 416 together.

As will be appreciated by a person of ordinary skill, radio accessnetwork 416 may be any type of mobile communications network, employingvarious network architectures and protocols such as those set out inmobile communications standards such as GSM, CDMA, GPRS, EDGE, W-CDMA,EVDO and the like. One or more radio access networks 416 may beincluded. Different radio access networks may provide differentservices.

Each PCD 420 is connected to a radio access network 416 via an airinterface, which provides PCD 420 with access to communications datasuch as multimedia streaming data that originates from streaming server410.

In operation, multimedia streaming data is sent to data network 412 bystreaming server 410. The source of the streaming data may be a livefeed source. A live feed may be from a signal source such as a TVbroadcast station, a microphone or video camera. The source of thestreaming data may also be pre-recorded multimedia data that is storedon persistent storage memory in streaming server 410 or other electronicstorage medium, such as an optical disk.

Streaming data may be first compressed and encoded before being sent bystreaming server 410 to data network 412. As will be appreciated by aperson of ordinary skill, streaming data may be encoded using a varietyof data formats including MPEG-4, Windows Media Video, Quicktime,RealVideo, MP3, and the like.

PCD 420 may be a cellular telephone, personal digital assistant,portable computer, other mobile handheld device, or the like. Due todifferences in processing power and display capabilities of suchdifferent portable electronic devices 420, streaming data may firstundergo transcoding in order to adapt streaming data for proper displayand presentation on a PCD 420. The transcoding process may include theconversion of multimedia data into a different data format, or adjustingdata properties such as data bit rate, frame rate, or frame size.Transcoding occurs before streaming data is received by PCD 420, and maybe implemented, for example, on streaming server 410.

FIG. 5 illustrates in more detail an exemplary embodiment of PCD 420, ahandheld communication device 422. As illustrated, device 422 includesinterconnected processor 424, memory 426, and RF transceiver 428. RFtransceiver 428 is adapted to send and receive signals via an airinterface connection with radio access network 416. Processor 424 isadapted to process communications signals and control the operation ofRF transceiver 428, and other components of device 422. The othercomponents may include an audio decoder 430, video decoder 432, clockgenerator 434, and power controller 436, each of which may beinterconnected with processor 424. Device 422 also includes a battery438 as a power source for providing power to the components of device422. Power controller 436 may control the operation of battery 438 andthe power modes in which different components of device 422 operate.

Processor 424 and decoders 430, 432 may form part of a circuit block 440for processing streamed data. As depicted, memory 426 is optionallyincluded in the same circuit block. In alternative embodiments, RFtransceiver 428 may also be included in block 440.

In the depicted embodiment, audio decoder 430 and video decoder 432 arecircuits suitable for receiving digital signals from processor 424 anddecoding such signals for eventual display on device 422. Video decoder432 is interconnected to display interface 442, which converts videosignals into a suitable format for display on display device 444.Similarly, audio decoder 430 is interconnected to audio output interface446, which converts audio signals into a suitable format for output onspeaker device 448.

Clock generator 434 produces a timing signal that drives the operationof processor 424. Timing signals of varying frequency may be generatedby clock generator 434, in order to speed up or slow down the operationof processor 424. Clock generator 434 may include a phase-lock loop(PLL). Clock generator 434 may also provide timing service to memory426, video decoder 432, audio decoder 430, display interface 442 andaudio output interface 446.

Power controller 436 may be interconnected to clock generator 434. Powercontroller 436 may throttle clock generator 434 or otherwise placeprocessor 424 into a reduced power consumption mode. Power controller436 may also provide voltage throttling, resource hibernation, orselective supply of power to various functional or circuit blocks indevice 422. For example, power controller 436 may switch off powersupply to an unused/inactive block, e.g. using a technique known aspower islands methodology. Power controller 436 may also provide powersupply at different voltages to different blocks (known as voltageislands methodology).

It is possible for device 422 to receive, process, decode and displaymultimedia streams in a reduced power consumption mode. This is possiblewhere the multimedia stream has been encoded, or transcoded into aformat that does not require device 422, or the circuit block 440, tooperate at its full processing capacity.

The processing capacity may be affected by a number of factors includingfor example, processor speed, free memory available to processor 424,and the available air interface bandwidth between radio access network416 and device 422.

During operation, in manners exemplary of the present invention, thestreaming server 410 may determine the processing requirements fordecoding and displaying a multimedia stream. If the processingrequirements are less than the full processing capacity, a low powermode indicator is sent by streaming server 410 to device 422, such as ina manner similar to that described above with reference to theembodiment shown in FIGS. 1 to 3.

In response to receiving the low power mode indicator, device 422 (orcircuit block 440) enters a lower power mode to decode and display themultimedia stream received from streaming server 410. By placing device422 in a lower power consumption mode to process multimedia streams thatdo not require device 422 to operate at its full processing capacity,overall power consumption is reduced. An example of such a lower powerconsumption mode may include a mode with a lower clock frequency, or alower operation voltage for processor 424.

FIG. 6 illustrates possible operations S600 performed by streamingserver 410 in manners exemplary of an embodiment of the presentinvention.

At S610, streaming server 410 receives processing capacity informationfrom device 420. The processing capacity may be measured using variousmetrics, either alone or in combination. For example, the instructionprocessing speed of processor 424 may be expressed as the rate at whichdata is processed in the form of a metric such as bitrate (e.g. in unitof bits per second), or frame rate (frames per second). In one example,the bitrate alone may be used to measure the processing capacity.Alternative metrics such as MIPS (millions of instructions per second)or MHz (millions of processor clock cycles per second) may also be used.The processing capacity information may be presented in the form of athreshold.

At S620, the processing requirements of a multimedia stream isdetermined by streaming server 410. A metric similar to that used atS610 for the processing capacity, such as the bitrate, may be used. Therequired processing capacity to decode and display a given multimediastream may be dependent on a number of properties of the multimediastream. For example, a video data stream using a higher bitrate, largerframe size, or higher frame rate may require greater processing capacityto decode and display. However, as will be appreciated by a person ofordinary skill, the particular data encoding format used to encode amultimedia stream may mean that a lower bitrate requires greaterprocessing capacity. For example, an encoding method with a more complexcompression scheme may result in a lower bitrate data stream, butrequire more processing cycles to decompress and decode.

In some situations, it is not necessary for device 422 to operate at itspeak processing levels in order to process all multimedia streams. AtS630, the processing requirements of a multimedia stream (determined atS620) is compared to the processing capacity of portable electronicdevice 422 (information received at S610). If the processing capacity ofdevice 422 is greater than the processing requirements of the multimediastream, power may be saved by placing device 422, or at least a portionof it such as circuit block 440, in a lower power mode.

Accordingly, at S640, if the processing capacity is greater than theprocessing requirements of the multimedia stream, a low power modeindicator is sent by streaming server 410 to device 422. The power modeindicator may be embedded in the multimedia streaming data or may besent as a separate signal to 422. The power mode indicator may specify aparticular voltage or speed at which processor 424 may operate in orderto process the upcoming multimedia stream. For example, a low power modeindicator may include a value indicating a preset mode, a lower voltage,or a lower processing speed (such as in MIPS or MHz). The preset modemay be one of a set of pre-determined power modes in which device 422can operate.

If full power is required to process the stream data, the power modeindicator may indicate a high, such as full, power mode. In this case,it is not necessary for the indicator to indicate any particularoperating parameter such as processor speed or voltage.

At S650, the multimedia stream undergoes transcoding, which may includethe conversion of multimedia data into a different data format, and theadjustment of data properties such as data bitrate, frame rate, or framesize. The transcoding process may be implemented on streaming server410, or on an intermediate server on the communications path to device422. The transcoded multimedia data is then sent to device 422.

FIG. 7 illustrates possible operations S700 performed by device 422. AtS710, device 422 sends processing capacity information to streamingserver 410. Device 422 may maintain various information related to itscapabilities, including for example, processor speed, operation voltage,the amount of memory available to processor 424, and the available airinterface bandwidth between radio access network 416 and device 422.Such processing capacity information may be sent to streaming server410, when the transmission connection between device 422 and streamingserver 410 is initially established. For example, the maximum processingspeed of processor 424 in bitrate, MIPS or MHz may be sent to streamingserver 410. Device 422 may also re-send updated processing capacityinformation to streaming server 410 during the period in which thetransmission connection is maintained, such as periodically or whenthere is a change. For example, the processing capacity of block 440 maychange due to activities of other components or a change in operationconditions.

At S720, device 422 determines whether a low power mode indicator hasbeen received from streaming server 410. If so, power controller 436 mayplace device 422 (or block 440) into a lower power mode at S730 prior todecoding the multimedia stream at S740. The lower power mode may includelower processor operation voltage, or processing speeds by reducing thefrequency of the timing signal produced by clock generator 434. Forexample, the low power mode indicator received from streaming server 410may specify a particular voltage, or processor speed such as in bitrate.In some embodiments, the speed may be measured in MIPS or MHz. Byreducing unnecessary processing cycles by lowering the operating voltageor the frequency of clock generator 434 to match the processingrequirements determined by streaming server 410, the overall powerconsumption by device 422 may be reduced, thus increasing the lifetimeof battery 438.

The processor operation voltage or speed may be adjusted with smallincrements. However, in some embodiments, it may be advantageous toadapt device 422 so that circuit block 440 can operate in a small numberof pre-determined power modes for different and discrete voltage orspeed levels within a given range. Device 422 may be adapted to operatein each one of the pre-determined power modes, for decoding anddisplaying multimedia streams with specific but different processingrequirements. The power mode indicator may specify one of thesepre-determined power modes. Furthermore, each of the pre-determinedpower modes may include the use of clock gating, voltage throttling,resource hibernation, power islands, voltage islands, and other knownmanners of power reduction of electronic components.

FIG. 8 illustrates alternative possible operations S800 performed bystreaming server 410 in manners exemplary of an embodiment of thepresent invention.

At S810, streaming server 410 receives processing capacity informationfrom device 422, specifically the available air interface bandwidthbetween radio access network 416 and device 422. This information may bereceived periodically, or in response to switching to a new radio accessnetwork 416, in order to determine any changes in the availablebandwidth. For example, the available air interface bandwidth maydecrease due to a mobile user moving into a geographical area causingdevice 422 to switch to a network with lower bandwidth. Availablebandwidth may also decrease due to poor radio reception or a change inthe traffic load conditions of radio access network 416. A decrease inbandwidth may result in a decrease in the multimedia stream processingcapacity of device 422. The maximum transmission bitrate may change dueto the change in bandwidth.

At S820, if a decrease in available air interface bandwidth is detected,multimedia stream transcoding parameters are adjusted at S830. Forexample, if the decrease in bandwidth results in an air interface thatis unable to support the bitrate of the multimedia stream, varioustranscoding parameters such as frame size or frame rate may be decreasedin order to provide a multimedia stream with a lower bitrate that can besuccessfully transmitted over the air interface. Since a lower bitratemay mean that the full processing capacity of device 422 is no longerneeded, a power mode indicator indicating a low power mode is sent bystreaming server 410 to device 422 at S840.

At S850, the multimedia stream undergoes transcoding and is sent todevice 422.

FIG. 9 illustrates corresponding alternative possible operations S900performed by device 422. At S910, device 422 sends processing capacityinformation to streaming server 410, specifically the available airinterface bandwidth between radio access network 416 and device 422.Device 422 may periodically send processing capacity information updatesto streaming server 410 in order to allow streaming server 410 todetermine any changes in the available bandwidth.

At S920, device 422 determines whether a low power mode indicator hasbeen received from streaming server 410. If so, power controller 436 mayplace device 422 into the corresponding low power mode at S930 prior todecoding the multimedia stream at S940.

Once the multimedia data is decoded, the decoded data may be presentedto the user.

As can be appreciated, in embodiments of the present invention, acontent server may transmit media content to a single PCD or maybroadcast media content to a number of PCDs.

Other features, benefits and advantages of the embodiments describedherein not expressly mentioned above can be understood from thisdescription and the drawings by those skilled in the art.

Of course, the above described embodiments, are intended to beillustrative only and in no way limiting. The described embodiments ofcarrying out the invention, are susceptible to many modifications ofform, arrangement of parts, details and order of operation. Theinvention, rather, is intended to encompass all such modification withinits scope, as defined by the claims.

1. A method of operating a portable communication device (PCD),comprising: receiving at the PCD, from a content server for transmittingmedia content, a power mode indicator indicative of a power modeselected from a plurality of power modes available to a circuit block insaid PCD, said circuit block exhibiting different levels of powerconsumption when operated in different ones of said power modes; andoperating said circuit block in said power mode in response to saidreceived power mode indicator.
 2. The method of claim 1, wherein saidplurality of power modes comprises a full power mode and at least onereduced power mode.
 3. The method of claim 1, wherein said contentserver is a stream server.
 4. The method of claim 3, further comprisingreceiving a data stream for a media content from said stream server; andprocessing said data stream for presentation of said media content to auser, as said data stream is being received, said circuit blockoperating in said power mode to perform at least one of said receivingand processing said data stream.
 5. The method of claim 4, wherein saidpower mode is selected based on at least a bitrate of said data stream.6. The method of claim 4, wherein said data stream comprises compresseddata, and said power mode is selected based on at least a compressionratio of said compressed data.
 7. The method of claim 4, wherein saidmedia content comprises video images and said power mode is selectedbased on at least a graphics resolution of said video images.
 8. Themethod of claim 7, wherein said data stream comprises a televisionbroadcast signal.
 9. The method of claim 8, wherein said televisionbroadcast signal comprises a sideband, said power mode indicator beingtransmitted in said sideband.
 10. The method of claim 4, comprisingtransmitting to said stream server data indicative of a processingcapacity, and wherein one of said least one reduced power mode isselected when said processing capacity is higher than needed to processsaid data stream.
 11. The method of claim 1, wherein said PCDcommunicates with said content server through wireless communication.12. A method of operating a content server for transmitting mediacontent, comprising: transmitting to a portable communication device(PCD) a power mode indicator indicative of a power mode that may beavailable to a circuit block in said PCD, said circuit block exhibitingdifferent levels of power consumption when operated in different powermodes; and transmitting data to said PCD.
 13. The method of claim 12,wherein said power modes comprise a full power mode and at least onereduced power mode.
 14. The method of claim 13, comprising receivingfrom said PCD data indicative of a processing capacity, and selectingone of said least one reduced power mode when said processing capacityis higher than needed by said PCD to process said data transmitted tosaid PCD.
 15. The method of claim 12, wherein said content server is astream server.
 16. The method of claim 12, wherein said transmittingdata to said PCD comprises transmitting a data stream for a mediacontent to said PCD, while said data stream is received and processed bysaid PCD for presentation of said media content to a user and saidcircuit block is operated in said power mode to perform at least one ofreceiving and processing said data stream.
 17. The method of claim 16,wherein said power mode is selected based on at least a bitrate of saiddata stream.
 18. The method of claim 16, wherein said data streamcomprises compressed data, and said power mode is selected based on atleast a compression ratio of said compressed data.
 19. The method ofclaim 16, wherein said media content comprises video images and saidpower mode is selected based on at least a graphics resolution of saidvideo images.
 20. The method of claim 19, wherein said data streamcomprises a television broadcast signal.
 21. The method of claim 20,wherein said television broadcast signal comprises a sideband, saidpower mode indicator being transmitted in said sideband.
 22. The methodof claim 12, wherein said PCD communicates with said content serverthrough wireless communication.
 23. A portable communication device(PCD) for media content, comprising: a circuit block operable in aplurality of power modes, said circuit block exhibiting different levelsof power consumption when operated in different ones of said powermodes; a receiver for receiving, from a remote content server, mediacontent and a power mode indicator indicative of a power mode selectedfrom said plurality of power modes; and a power management module forsetting said circuit block to operate in said power mode in response toreceiving said power mode indicator.
 24. The PCD of claim 23, which is acellular telephone.
 25. The PCD of claim 24, wherein said content serveris a stream server.
 26. The PCD of claim 25, wherein said circuit blockis operated in said power mode to perform at least one of receiving andprocessing streamed data.
 27. A content server for transmitting mediacontent comprising: a power mode selector for selecting a power modeindicator indicative of a power mode selected from a plurality of powermodes potentially available to a circuit block in a portablecommunication device (PCD), said circuit block exhibiting differentlevels of power consumption when operated in different ones of saidpower modes; and a transmitter for transmitting to said PCD said powermode indicator and data.
 28. The content server of claim 27, whereinsaid content server is a stream server.
 29. The content server of claim28, wherein said power mode indicator is associated with a data streamfor media content to be transmitted to said PCD such that said circuitblock is operable in said power mode to receive or process, or bothreceive and process, said data stream for presentation of said mediacontent to a user.